Intent to ship: Windows UI Automation

[James Teh]

It's unclear whether this needs an intent to prototype/ship given that it isn't a feature exposed to web content. However, after some discussion, it certainly can't hurt to provide notice even if it's not required.

As of Firefox 143, I intend to turn Windows UI Automation on by default.

Summary:  UI Automation (UIA) is Microsoft's recommended accessibility framework for Windows, replacing the earlier Microsoft Active Accessibility (MSAA) framework. Although it is not yet used for the web by popular screen readers such as NVDA and JAWS, it is used by an increasing number of applications, including accessibility tools built into Windows such as Narrator, Text Cursor Indicator, Windows Speech Recognition and Voice Access. Furthermore, it is used by Windows features not specifically targeted at accessibility such as Suggested Actions and Snap Layouts. It offers several advantages over older frameworks including increased performance and security.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=762769

Specification: UIA is not a web or open standard, though mappings for web content are standardised by the W3C ARIA Working Group:

  Microsoft documentation: https://learn.microsoft.com/windows/win32/winauto/entry-uiauto-win32

  Core Accessibility API Mappings 1.2: https://w3c.github.io/core-aam/

Platform coverage: Windows only, exposed to external accessibility clients (not a web API)

Preference: accessibility.uia.enable (0 to disable, 1 to force enable, 2 to enable unless an incompatible client is detected)

DevTools bug: not applicable; not relevant to web developers. Any inspection, debugging, etc. specific to UIA is performed using Windows specific tools.

Other browsers:

  Edge: shipped (version unknown)

  Chrome: Chrome 138, https://developer.chrome.com/blog/windows-uia-support-update?hl=en

  WebKit: not applicable; UIA is Windows only

web-platform-tests: Not currently testable with WPT, but this should eventually be possible to some extent; see: https://github.com/web-platform-tests/wpt/pull/53733

Security & Privacy Concerns: Exposes the same information already available to accessibility clients using other accessibility APIs across all supported platforms. Doesn't expose anything to web content.

Jamie